1. Field of the Invention
The present invention relates to an organic-metal-compound-containing solution used in manufacturing an electro-emitting device, and to methods of manufacturing an electron-emitting device, an electron source, and an image forming apparatus using the organic-metal-compound-containing solution and, more particularly, to the manufacturing method using an ink-jet method and the solution used in the manufacturing method.
2. Related Background Art
As conventional electron-emitting devices, two types of electro-emitting devices, i.e., a thermionic emission device and a cold-cathode emission device, a field emission type device (to be referred to as xe2x80x9cFE typexe2x80x9d hereinafter), a metal/insulating layer/metal type (to be referred to as xe2x80x9cMIM typexe2x80x9d hereinafter) emission device, and a surface conduction type electron-emitting device are known. For example, as an FE type device, a device disclosed in W. P. Dyke and W. W. Dolan, xe2x80x9cField Emissionxe2x80x9d, Advances in Electronics and Physics, 8, 89 (1956), C. A. Spindt, xe2x80x9cPhysical Properties of Thin-Film Field Emission Cathodes with Molybdenum Cones:, J. Appl. Phys., 47, 5248 (1976), or the like is known.
As an MIM type emission device, a device disclosed in C. A. Mead, xe2x80x9cOperation of Tunnel-Emission Devices,xe2x80x9d J. Appl. Phys., 32, 646 (1961) or the like is known.
As a surface conduction type electron-emitting device, a device disclosed in M. I. Elinson, xe2x80x9cThe Emission of Hot Electrons and the Field Emission of Electrons from Tin Oxide,xe2x80x9d Radio Eng. and Electron Pys., 10, 1290 (1965) or the like is known.
A surface conduction type electron-emitting device uses a phenomenon in which electron emission occurs by causing a current to flow into a small thin film formed on a substrate in a direction parallel to the film plane. As the surface conduction type electron-emitting device, the above electron-emitting device using an SnO2 thin film and obtained by Elinson, an electron-emitting device using an Au thin film [G. Dittmer, xe2x80x9cElectrical Conduction and Electron Emission of Discontinuous Thin Films,xe2x80x9d Thin Solid Films, 9, 317 (1972)], an electron-emitting device using an In2O3/SnO2 thin film [M. Hartwell and C. G. Fonstad xe2x80x9cStrong Electron Emission from Patterned Tin-Indium Oxide Thin Films,xe2x80x9d IEEE Trans. ED Conf., 519 (1975)], an electron-emitting device using a carbon thin film [Hisashi Araki et al., xe2x80x9cElectroforming and Electron Emission of Carbon Thin Films,xe2x80x9d Journal of the Vacuum Society of Japan, Vol. 26, 1, 22 (1983), or the like has been reported.
As a schematic device arrangement of the above surface conduction type electron-emitting devices, the device arrangement obtained by M. Hartwell will be described below with reference to FIG. 7. Referring to FIG. 7, reference numeral 1 denotes a substrate. Reference numeral 4 denotes an electroconductive thin film consisting of a metal oxide thin film or the like formed by sputtering in an H-shaped pattern. The electroconductive thin film 4 is subjected to a current conduction treatment called energization forming to form an electron emission portion 5. The length L and width Wxe2x80x2 of the device in FIG. 7 are set to about 0.5 mm to 1 mm and about 0.1 mm, respectively.
In the above conventional surface conduction type electron-emitting device, before electron emission is performed, the electroconductive thin film 4 is generally subjected to a current conduction treatment called energization forming to form the electron emission portion 5. More specifically, in the energization forming, a DC voltage or a voltage which very slowly increases, e.g., about 1 V/min., is applied across both ends of the electroconductive thin film 4 to energize the electroconductive thin film 4, and the electroconductive thin film 4 is locally broken, deformed, or deteriorated to form the electron emission portion 5, which is in an electrically high resistance state. In the electron emission portion 5, fissures are formed in a part of the electroconductive thin film 4, and electron emission occurs from a portion near the fissures. In the surface conduction type electron-emitting device which has been subjected to the energization forming treatment, a voltage is applied to the electroconductive thin film 4 to cause a current to flow into the device, thereby causing the electron emission portion 5 to emit electrons.
As a method of forming the electroconductive thin film, a method of directly forming an electroconductive material on a substrate by thin film deposition such as vacuum evaporation or sputtering is known. As another method, a method of coating a solution of an organic metal compound or the like on a substrate and heating to decompose it into a metal or a metal oxide is known. According to these methods, since a vacuum apparatus for film formation is not required, advantages in production such as a reduction in manufacturing cost, can be obtained.
As described above, to apply an organic metal compound solution on a substrate to form an electroconductive film, the following patterning method is used. That is, after a mask having an opening having a predetermined pattern is formed on the substrate, the organic metal compound solution is coated on the substrate by dipping, spin-coating, spray-coating, or the like, and the coated film is heated and decomposed to obtain a metal or a metal oxide. Thereafter, the mask is removed to obtain an electroconductive film having a predetermined shape. However, if the solution coated on the entire surface of the substrate need not be patterned, then when an electron source in which a large number of devices are arranged on a large substrate is to be manufactured, advantages in manufacturing can be obtained.
It is an object of the present invention to provide a method of manufacturing an electron-emitting device which can be manufactured in simple processes at a low cost, and a method of manufacturing an electron source and an image forming apparatus using the electron-emitting device.
It is another object of the present invention to provide a method of manufacturing an electron-emitting device having good mass-production properties and an increased yield, and a method of manufacturing an electron source and an image forming apparatus using the electron-emitting device.
It is still another object of the present invention to provide a method of manufacturing an electron-emitting device having good electron emission characteristics, and a method of manufacturing an electron source and an image forming apparatus using the electron-emitting device.
It is still another object of the present invention to provide a method of manufacturing an electron-emitting device in which a solution containing water as a main component and an organic metal compound is applied as a droplet by a (bubble jet) BJ device to form an electroconductive film for the electron-emitting device, and a method of manufacturing an electron source and image forming apparatus using the electron-emitting device.
It is still another object of the present invention to provide a manufacturing method which suppresses the pattern of an obtained electroconductive film from being different from a desired one due to deformation of the pattern of a droplet after a solution is applied or a difference between wettabilities of the solution to a substrate surface and a electron surface in the above manufacturing method.
The present invention which has been made to achieve the above objects provides a method of manufacturing an electron-emitting device including an electroconductive film having an electron emission portion and arranged between electrodes, characterized in that the step of forming the electroconductive film has the step of applying a solution containing an organic metal compound including a metal element and an amino acid group and water to a portion between electrodes arranged on a substrate by using an ink-jet method which gives heat to the solution to discharge the solution, drying the applied solution, and then decomposing the compound.
According to the present invention, there is provided a method of manufacturing an electron source including an electron-emitting device having an electroconductive film having an electron emission portion and formed between electrodes, and voltage applying means for applying a voltage to the electron-emitting device, characterized in that the electron-emitting device is manufactured by the above method.
According to the present invention, there is provided a method of manufacturing an image forming apparatus including an electron source comprising (1) an electron-emitting device having an electroconductive film containing an electron emission portion and arranged between electrodes, (2) voltage applying means for applying a voltage to the electron-emitting device, and (3) a light-emitting member which receives electrons emitted from the electron source to emit light, characterized in that the electron-emitting device is manufactured by the above method.